On some roads my XTR is jarring my spine a bit and causing me to get a headache and a "cracky" neck. I don't get this on my BMW!

Before I start thinking what to replace, I was wondering if I should increase the rear preload. With my riding gear, I'm 100kg and my preload is set to 2 out of 5, the standard setting with 1 being soft and 5 being hard. I wondered whether I would benefit from increasing the preload a notch. I guess 100kg is a bit heavier than average for this bike.

Have any of you guys who understand suspension better than me set your preload for your weight with good results? If so, please post your weight and preload setting!

Thanks!